One technique to optimize bandwidth usage and save computing resources involves responding to a request for a web page by looking to what information a client device may have already received from a server at an earlier point in time. Information included in a document may be distinguished from other information included in that same document by looking to how frequently the information changes and whether a user has the most recent version of that part of the document. Using these criteria, information in a document may be categorized as either (1) template information (including information that changes infrequently) or (2) delta information (including information that changes relatively frequently or is somehow personalized with respect to a user). Differential caching and service of template and delta information results in a saving of bandwidth and other computing resources because information that does not change frequently may be compressed and cached at a server that is relatively proximate to one or more end users.
Differential caching based upon the distinction between template information and delta information does not necessarily result in a substantial savings of bandwidth and computing resources under all conditions, particularly under those conditions when amount of delta information exceeds the amount of template information. For example, different elements in a personal web page, such as those provided by Yahoo, may change at very different rates with respect to each other.
For example, the headline stories presented to a user may change every hour, whereas elements associated with the user's decision to view a particular topic may change only occasionally, and still other elements (such as the title bars in a page or logos associated with the provider of the content) may change very rarely. Under these circumstances, the template contains relatively little information compared to the amount of delta information. Under these circumstances, differential caching may not significantly reduce the amount of bandwidth and other resources needed to transmit a web page because a large part of the page must be freshly obtained from the content delivery network or re-compressed every time it is transmitted.
Accordingly, it would be desirable to provide a technique for efficiently serving relatively non-static content in a content delivery network that does not suffer from the drawbacks of the known art.